It is known to provide a launch control clutch for selectively coupling an output shaft of an internal combustion engine to an input shaft of a vehicle transmission. The clutch comprises friction plates which are brought into contact with each other when the clutch is engaged to drivingly couple the shafts. To accommodate the speed differential between the input and output shafts, the friction plates are allowed to slip in relation to each other, thereby allowing the speed of the shafts to be matched progressively. The relative movement of the friction plates generates considerable heat which can potentially damage the clutch and, in the case of wet clutches immersed in a lubricating fluid, may result in degradation of the lubricating fluid. The problem of heat generation is particularly significant at low vehicle speed (for example <15 kph) when high torque is required. This combination is often encountered by four-wheel drive vehicles, for example during a hill start on a steep incline or towing a heavy load up an incline. These vehicles may have a transfer case to enable operation in high and low ranges; and a central differential to control the delivery of torque to the front and rear driven wheels.
A known approach for managing heat generated within the transmission is to control the output torque from the internal combustion engine. Alternative approaches include controlling the transmission, for example to disable double-gear changes; to slow gear changes; and to inhibit gear changes. These techniques rely on inhibiting functionality and this may be undesirable in certain driving scenarios, for example when towing heavy loads.
It is against this backdrop that the present invention has been conceived. At least in certain embodiments, the present invention sets out to overcome or ameliorate at least some of the shortcomings associated with prior art systems.